Field of the Invention
The present invention relates to a chuck table for holding a flat surface of a workpiece under suction, and a method of manufacturing a suction plate of porous ceramics that serves as part of such a chuck table.
Description of the Related Art
It has been customary to grind the reverse side of a wafer, which has a plurality of devices such as integrated circuits (ICs), large scale integration (LSI) circuits, or the like formed on a face side thereof and demarcated by projected dicing lines, with a grinding apparatus until the wafer is ground to a predetermined thickness, form division starting points in the wafer with a laser processing apparatus, and apply external forces to the wafer to divide the wafer into individual device chips, which will be used in electric appliances such as mobile phones, personal computers, etc.
The laser processing apparatus generally includes an air-permeable chuck table for holding a wafer thereon, laser beam applying means for irradiating the wafer held on an attractive suction surface of the chuck table with a laser beam having a wavelength with which the wafer is permeable, X-axis moving means for moving the chuck table and the laser beam applying means relatively to each other in X-axis directions, and Y-axis moving means for moving the chuck table and the laser beam applying means relatively to each other in Y-axis directions. The laser processing apparatus is capable of forming modified layers that provide division starting points in the wafer along the projected dicing lines (see, for example, Japanese Patent No. 3408805).